Search
Close this search box.

BUNDLE BRANCH BLOCK

What Is a Bundle Branch Block?

To better understand a bundle branch block, it is important to understand how the heart works:

  • The heart is made up of four chambers: two atria (upper chambers) and two ventricles (lower chambers).
  • Electrical impulses from your heart muscle cause your heart to beat (contract).
  • This electrical signal begins in the sinus node, which is located at the top of the right atrium.
  • The sinus node is responsible for starting a heartbeat and is the body’s natural pacemaker.
  • When an electrical impulse is released from this natural pacemaker, it causes the atria to contract.
  • The signal then passes through the atrioventricular (AV) node, through the bundle of His, and down the bundle branches (which are like the trunk of a tree).
  • The signal then passes through the Purkinje fibers (which are like branches on a tree) to the muscle fibers of the ventricles, causing them to contract.
  • An analogy for the normal conduction system of the heart would be to imagine a picture made up of dominos. One domino is pushed over, causing a wave of collapsing dominos that spread out across the picture until all dominos are down. In this same way, all the cells in the heart receive an electrical stimulus, causing them to contract.

Types of Bundle Branch Blocks

  • The medical terms for bundle branch block are derived from which branch is affected.
  • If the block is located in the right bundle branch, it is called right bundle branch block.
  • If the block is located in the left bundle branch, it is called left bundle branch block.

How Is a Bundle Branch Block Diagnosed?

The electrical patterns from an electrocardiogram (ECG) can show a bundle branch block and whether the block is located in the right or left bundle branch.

What Causes Bundle Branch Block?

  • Left bundle branch block usually is a reflection of damage to the left ventricle caused by high blood pressure, a heart attack, a failing aortic valve, coronary artery disease, heart failure, or other cardiac conditions. Treatment focuses on the cause of the block.
  • Right bundle block happens more often in older people but can also be seen in healthy young people. It may occur with natural degeneration of the heart’s conduction system that occurs with age. It can also occur in people who have another underlying heart or lung problem.

What Are the Symptoms of a Bundle Branch Block?

  • If there is nothing else wrong with your heart, you probably will not feel any symptoms of bundle branch block. In fact, some people may have a bundle branch block for years and never know they have the condition.
  • In people who do have symptoms, they may faint (syncope) or feel as if they are going to faint (presyncope).

How Is Bundle Branch Block Treated?

  • In healthy people without apparent heart disease, right bundle branch block does not appear to have a significant effect on mortality. You may not need any treatment at all for right bundle branch block.
  • In people with known or suspected cardiovascular disease, a bundle branch block is associated with a greater risk of death, especially after a heart attack. After a heart attack, your heart is fragile, and bundle branch block may cause a very slow heart rhythm (bradycardia).
  • For patients with both bundle branch block and dilated cardiomyopathy, a type of pacing called cardiac resynchronization treatment (CRT) may be beneficial. Normally, pacemakers pace only one of the lower heart chambers (the ventricles) at a time. But CRT re-coordinates the beating of the two ventricles by pacing them at the same time.

Choose Your Preferred Location

Receive the exceptional care you deserve today.